This invention relates to cleaning methods and apparatus, and more particularly relates to methods and means for cleaning interior surfaces of railroad tank cars and the like, and also stripping rubber linings and the like affixed to these interior surfaces.
It is well known in the prior art that a diversity of commodities are transported by land in railroad tank cars, truck trailers, transport tankers, etc. It is also well known in the prior art that there are special purpose railroad tank cars and the like which are lined with rubber and the like, to prevent contamination, chemical reactions, etc.
Prior to being filled or loaded with a particular commodity, a tank car and the like must be thoroughly cleaned for health and safety reasons. Tank cars with linings must, of course, also be cleaned and, indeed, such linings may be stripped and replaced prior to being filled or loaded with another commodity. Such cleaning and stripping have heretofore conventionally been both labor-intensive and time-consuming.
During typical manual cleaning, the flow of liquid through hand-held hoses is limited to volumes of less than approximately 7 gallons per minute. This throughput is not only limited by a worker's handling ability, but also is limited by the unstable standing conditions in a slippery, conventional rounded-bottom tank car. Indeed, considering that typical manual car-wash volumes of water are only 2 gallons per minute at low pressures of 1,500 psi, a 7 gallon per minute flow presents a considerable challenge to a worker, particularly within the confines of a tank car and the like. Furthermore, there are hazards to workmen from splashing chemicals, debris, fumes, and even explosions. Thus, in addition to being an inherently hazardous and slow method of cleaning tank cars, such manual methods are inherently nonuniform and unreliable.
Accordingly, there have been several attempts in the art to automate the cleaning and stripping of tank cars and the like. To clean the interior of a tank car with reduced human intervention. However, requires that a suitable apparatus either be a permanent member thereof or be inserted and then assembled therein. As should be evident to those conversant with the art, entry into a railroad tank car is routinely available through a narrow manway located on top thereof or could be rendered expedient through a specially designed wall or side panel or door. But, of course, a tank car with such a specially designed panel or door would necessitate structural modifications and would be susceptible to contamination and leakage.
An apparatus designed to eliminate or minimize such danger to workmen is illustrated by Hulbert in U.S. Pat. No. 3,571,985. Specifically intended to clean tank car linings with an abrasive material like sand, Hulbert discloses an apparatus consisting of a support structure affixed to the ends of a tank car using hydraulics and pneumatics. A pneumatic pump provides for longitudinal movement of a carnage along the support structure, while another pneumatic pump simultaneously provides for independent rotational movement of a plurality nozzles. Drive means are also provided for the manual control of linear carriage advancement and rotational nozzle spray pattern. A vacuum pump removes debris from the floor of the tank car. Since considerable time appears to be prerequisite to assembling the Hulbert apparatus, it is probably intended not to be portable, but to be a relatively permanent fixture in a tank car.
As another example, Saxonmeyer, in U.S. Pat. No. 3,461,889, teaches an apparatus for washing railway tank car interiors which provides for the entry through a side door in the tank car of a platform movably mounted by a base and a carriage movably mounted with respect to the platform. A boom assembly mounted on the carriage controls the spray of liquid about a vertical axis through plurality of nozzles. The Saxonmeyer apparatus includes sensing axis to provide semi-automatic operation by limiting its washing operation only to times when a side edge of the tank car door opening is not contacted.
While improving the prior railway tank car cleaning art, the Hulbert and Saxonmeyer devices have provided only limited arcuate manipulation of the spray nozzles and require structural modifications to a railroad tank car. Guigon et al., in U.S. Pat. No. 3,444,869, disclose a jet cleaning device which attempts to improve the effectiveness and nature of the spray for cleaning purposes. Based upon a complicated plurality of oscillatable nozzles, this device has a corresponding plurality of streams of cleaning liquid which is directed to the internal surfaces of a tank car. The sizes of these streams depends upon the distances of the plurality of nozzles from tile internal surfaces therefrom.
Another improvement in the nozzle manipulation art is disclosed by Jaeger in U.S. Pat. No. 3,895.756. In particular, there is disclosed a method and apparatus for cleaning vessels which not only enables presetting control means to accommodate a vessel's dimensions, but also enables programming a sequence of nozzle movements. The Jaeger apparatus is lowered into a tank car through its manway and the assembly connected by liquid pressure lines to a control device and to a source of pressurized cleaning fluid. A high pressure spray nozzle is mounted for universal movement relative to two perpendicular axes. Separate hydraulic actuators are connected to and activated from a remote control device, which is air operated and with means for adjusting the speed and degree of sweep of the spray nozzle, thereby enabling a spray of any configuration to be generated. Thus, in addition to providing more versatile manipulation and control of spray nozzles, the Jaeger apparatus is portable and is inserted into a tank car through its manway.
Similarly, in U.S. Pat. No. 3,001,534, Grant teaches a portable apparatus for cleaning a tank car by being inserted thereinto. A baseplate temporarily replaces a tank car's dome cover and supports an assembly extending into the interior of the car and carrying rotating spray heads. These spray heads are driven by an electric motor and rotate about two orthogonal axes, thereby permitting water spray throughout a tank car's interior. Thus, in addition to improving the prior art with a portable top-insertable apparatus, the Grant apparatus is easily positioned within the tank car and directs a controllable, compound water spray pattern throughout the interior thereof using swivel means. The number of revolutions of the swivel means is determined by the relative ratios of two sets of pinions and gears.
Further improvements in the prior art are disclosed by Looper and Maton. In U.S. Pat. No. 4,244,523, Looper teaches a top-inserting apparatus for conveniently and inexpensively cleaning rubber-lined tank cars. This apparatus consists of a fixed frame for supporting a tiltable frame from which extends a pivotally mounted wash nozzle assembly containing a cleaning liquid tube at the end of which is connected spray nozzles. The spray jets operate simultaneously on longitudinal and transverse axes of the tank car promoting thorough cleaning thereof. Similarly, in U.S. Pat. No. 4,341,232, Maton discloses a tank cleaning apparatus which limits the rotation of top-insertable spray arms to 180.degree. instead of the conventional 360.degree.. By only rotating spray arms through 180.degree. during the washing cycle, matter dislodged from the interior of a tank car is prevented from being forced upon already cleaned surfaces because a spray pattern is formed which directs such dislodged material to one end of the car or to its bottom.
Notwithstanding these improvements in the tank cleaning and stripping art, there is still not available an automatic and reliable apparatus and method cleaning tank cars and the like and for stripping the linings therein contained. It would be advantageous for an apparatus to be sufficiently portable to be completely inserted through an existing manway and then be conveniently and quickly assembled therein. It would also be advantageous for such an apparatus to be readily configured so as to accommodate tank cars of various lengths and diameters, and having various size thermal wells.
Those skilled in the art would also appreciate the utility of an apparatus capable of generating and accurately controlling a high pressure and high volume liquid spray such that the entire interior surfaces of a tank car and the like would be effectively treated, even containing a lining thereon. Such effective liquid spray would preclude the present conventional use of abrasive cleaning of linings, thereby significantly prolonging the longevity thereof. It would be further advantageous if such apparatus were driven within the tank car by a nonelectrical motor to avoid a potential safety hazard due to sparks causing combustion or explosion.
Accordingly, these limitations and disadvantages of the prior art are overcome with the present invention, and improved means and techniques are provided which are useful for cleaning and stripping residue, contaminants, debris, etc. from all of the interior surfaces in a railway tank car and the like, such that the means may be conveniently lowered into a tank car through its manway and, after quick assembly thereof, pneumatically configured to accommodate the particular physical dimensions of the tank car, and then be preset for automatic cleaning and/or stripping operation.